What happens to your body and brain when you get hypothermia

Hypothermia: it's something you see all too often in movies starring Leonardo DiCaprio. But what is it, exactly? And how does it really happen?

Our body is always trying to maintain a balmy temperature of around 98.6℉ or 37°C. Hypothermia occurs when our body loses heat faster than we can produce it. And hypothermia doesn't only strike sinking-ship victims and 19th-century fur-trappers wandering in the wilderness.

Studies estimate about 1,500 Americans die of accidental hypothermia each year. In fact, exposure to cold is responsible for twice as many deaths as heat exposure annually. Young children and the elderly are especially vulnerable. So, why is hypothermia so dangerous?

Most heat loss occurs when unprotected surfaces radiate heat away from the body. In addition, wearing wet clothes makes heat loss even worse. And wind chill can quickly escalate the situation because it strips away the thin layer of heat on the skin's surface. As your temperature drops, your body and brain fire back.

Your thyroid and adrenal glands release a flood of hormones that boost your metabolism, heart rate, and blood pressure. In the brain, the hypothalamus tells your blood vessels to constrict. This moves the blood farther from the skin's surface, where its heat can escape. Your hypothalamus also signals your muscles to shiver, which kicks your metabolism into overdrive, 2-5 times the normal rate.

At this point, you're on the brink. If you don't get to safety soon, you'll hit severe hypothermia and be in serious trouble. Eventually, even your brain will grow colder. When that happens, it stops functioning properly which can make you feel dizzy, disoriented, and even want to strip naked.

Before too long, you run the risk of permanent brain damage. But just how long do you have? It's hard to know because each situation and person is different.

However, radiologist Anna Bagenholm currently holds the record for surviving the coldest body temperature. After a skiing accident, she endured 80 minutes in freezing cold water. Her body temperature had plummeted to 56.7 ºF or 13.7ºC. Hopefully, that never happens to you, but here are some tips for treating hypothermia with several safety measures.

Immediate first aid. Victims can also be treated with warm IV fluids and saltwater solutions.

And you can help to avoid hypothermia with some safety measures, like wearing appropriate clothing, avoiding overexertion in cold conditions, and letting people know what time you expect to arrive.

Run smart, travel smart, and dress smart — even if it makes you look like a giant marshmallow.